Al-Si-Ni Electrodes Prevent Diffusion in OLED Displays
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Solution Overview
Problem
In organic light emitting displays, the diffusion of metal materials used for source and drain electrodes into the active layer causes short-circuiting and deteriorates channel characteristics, while high contact resistance between these electrodes and the first electrode hampers performance.
Innovation Solution
The use of aluminum alloys containing nickel and silicon, or germanium and gadolinium, for the source and drain electrodes, along with Indium Tin Oxide (ITO) layers, prevents diffusion and reduces contact resistance by inhibiting the formation of aluminum oxide and galvanic corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum is used to form source and drain electrodes for low resistance, then electrical conductivity is improved, but metal diffusion into the active layer causes short-circuiting and deteriorates channel characteristics
Solution Approach 1:
The patent applies composite materials by using an aluminum alloy consisting of Al-Si-Ni system instead of pure aluminum. The specific composition (Al: 96-98 wt%, Si: 1-3 wt%, Ni: 1-3 wt%) creates a composite structure that combines the low resistance property of aluminum with the diffusion barrier properties of silicon and nickel, thereby preventing metal diffusion into the active layer while maintaining electrical conductivity.
Solution Approach 2:
The patent changes the material parameters by introducing specific alloying elements (Si and Ni) in controlled concentrations. The silicon content of 1-3 wt% and nickel content of 1-3 wt% are optimized to prevent diffusion while maintaining low resistance. This parameter modification transforms the material properties to simultaneously achieve conductivity and diffusion prevention.
2Device complexity
If a single metal layer is used for source and drain electrodes, then device complexity is reduced, but contact resistance with ITO increases due to oxide formation
Solution Approach 1:
The patent uses a composite aluminum alloy material (Al-Si-Ni) that inherently prevents oxide formation through the presence of silicon and nickel. These elements form a protective barrier that prevents aluminum oxidation, thereby maintaining low contact resistance with ITO while keeping the electrode structure as a simple single layer, avoiding the need for multi-layer complex structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively prevents material diffusion into the active layer, reduces contact resistance, and enhances electrical characteristics by maintaining optimal nickel, silicon, or gadolinium concentrations in the electrodes.
Implementation Method 1
Each source electrode and drain electrode includes an aluminum alloy containing nickel and silicon
Implementation Method 2
when each of the source and drain electrodes is formed of a single metal, Al, an oxide is formed on a surface of each of the source and drain electrodes, thereby further increasing contact resistance between Al and ITO
Data Source
AI summary
An organic light emitting display that prevents a material used to form a source electrode and a drain electrode from being diffused into an active layer and reduces contact resistance between the source and drain electrodes and a first electrode includes: a substrate; an active layer arranged on the substrate and including silicon; a gate electrode arranged on the substrate and insulated from the active layer; a source electrode and a drain electrode each of a single layer structure, insulated from the gate electrode, and electrically connected to the active layer; a first electrode electrically connected to either the source electrode or the drain electrode; an organic light emitting layer arranged on the first electrode; and a second electrode arranged on the organic light emitting layer, each source electrode and drain electrode includes an aluminum alloy containing nickel and silicon.